Construction of molecular basis of reproductive endocrine system of shark and application to artificial spawning technology

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K07472
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Morphology/Structure
• Research Institution: University of Miyazaki
• Principal Investigator: UCHIDA Katsuhisa 宮崎大学, 農学部, 教授 (50360508)
• Co-Investigator(Kenkyū-buntansha): 森山 俊介 北里大学, 海洋生命科学部, 教授 (50222352)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 板鰓類 / 繁殖生理学 / 進化 / 生殖ホルモン / 孵化酵素 / 卵殻腺

Outline of Final Research Achievements

To develop the artificial spawning technology for sharks, we aimed to understand the molecular background of the reproductive endocrine system and the functional aspect of eggshell gland hatching glands, which have not been elucidated so far. First, we histologically showed the four functional secretory layers of the eggshell glands of the female cloudy catshark, Scyliorhinus torazame and indicated that the major secretory layer contributes to collagen synthesis at the molecular level. Second, we identified three GnRH genes and four GnRH receptor genes from the shark brain, and demonstrated that shark GnRH may regulate the pituitary FSH functions. Thirdly, we have identified the hatching gland in the head of the catshark, and have revealed the molecular structure of hatching enzyme that expressed in epithelial cells of hatching gland for the first time in sharks by next-generation sequence analysis.

Free Research Field

比較内分泌学

Academic Significance and Societal Importance of the Research Achievements

本研究の成果により、サメ類の生殖輸管系と生殖関連ホルモンの機能や胚の孵化に関する仕組みの一端が理解できた。これらの成果は、単に、トラザメの繁殖生理・内分泌機構に関する知見の発信に留まらず、真骨魚類での先行知見との比較や、軟骨魚類から卵生の陸棲脊椎動物へと引き継がれた卵殻形成機構の分子基盤とその進化の理解に繋がり、基礎動物学や繁殖生理学、比較内分泌学分野に新たな知見と学術進展を発信できると考える。また、近い将来、本研究の成果は、トラザメの人為産卵促進技術の開発に繋がると考えられ、世界のサメ繁殖生理学研究を牽引し、サメ資源の保護や増産のための方策を生み出すことが可能と考えている。